Lubricant



Oct-30, 1945. M REgwlc'K j 2,388,083

LUBRICANT V Filed April 5, 1941.

do TOTAL VOL UML or cue/GINA. EMuLsmV TOTAL 4122' con TENT 'flMou/vr or WATER 3434248729 3 rnon an. 4316A! k JAN; HTHE/VA rs V x v 1 200 k Y OLEATE z ,1 8 0 1 8 z r 3 H0 025 $774 [VD/Nd MAuRlc s Riswma 5W Patented Oct. 30, 1945 UNITED STATES PATENT OFFICE nuaarcsn'r Maurice Reswlck, New Brighton, Staten Island, N. 1., assignor to Standard Oil Development Company, a corporation of Delaware Application April 5, 1941, Serial No. 387,008

' .6 Claims. (Cl. 252-37) This invention relates to novel lubricants and i to methods of preparing and using same.

1 There are many industrial uses for lubricants where the lubricating composition comes in contact with water or. other aqueous fluids which tend to wash away the lubricant by emulsiflcation or otherwise. thereby impairing lubrication 35 performance. This is especially true;lor instance, -ln steel mills where the approach tables on hot strip mills are subjected to a spray of high pressure water used for cleaning the scale oi! the hot rolled steel. This water gets into the roll bearings and gear cases and emulsifles with the lubricant, causing it to. overflow and gradually become more dilute until eventually it is insumcient for lubrication The present invention has for oneoi its 1111- 45 mary objects the preparation of lubricants which have water-repellent properties which make them especially suitable for lubrication of machinery operated either in water, or in continuous or at least occasionailcontact with water. 50 Another object or this invention is to prepare lubricants not only having water-repelling properties but also having .extreme pressure lubricant characteristics, by which is meant the ability to lubricate metal parts which move in contact with 55 each other under extremely high pressure or heavy loads. Another object of this invention 30 is to prepare lubricants oi the above types which are especially resistant to water which contains .high amounts of acid and mineral salts or other" i materials which normally promote emulsiiication of mineral oil and water, as, for instance, is the 5 case with the water in the Monongahela River near Pittsburgh, Pennsylvania, which contains considerable amounts oi iron and calcium andoperations).

varying amounts or free acid (mostly sulfuric,

probably .from coal mining and steel pickling 40 Samples of Monongahela River water taken in the vicinity oi Homestead, Pennsylvania, over a period or a year, show the follow- 'ingrangesinanaiysis(expresseding'rainsper- Total acidity- 0.3 to 3.1 so F0804 0.1 to 0.4 Al:(804): 0.1 to 2.3 Hardness 3.5 to 10.6

"ln twoinstances when the total acidity was 3.1, the free acid was found to be 0.4 and 0.5. Another sample of Monongahela River water analysed more in detail as to mineral constitu entsshowed the following analysis:

Iron, per cent (as Pesos) 0.009

Calcium. per cent (as CaO) 0.004

Magnesium, per cent (as MgO) 0.0005

Sodium. per cent 0.002 Sulfate ion, per cent 0.0132 (Equivalent as sulfuric acid, per cent) 0.0135

Chlorideion, per cent 0.0023

Broadly, the'invention comprises a mineral lubricating oil base stock with a heavymetal naphthenate soap and a small amount oi hydroxy aromatic compound. More specifically the invention may be illustrated by a lubricant comprising a mador proportion of minerallubricating oil, about 15% oi lead naphthenate and about 2% of cresol.

The mineral lubricating oil base stock tobe used may be obtained from any of the crude petroleian stocks normally usedsuch as the pars aillnic'base oils, e. g., Pennsylvania crudes, naphthenic base oils, e. Calllornia and Venemelan, and mixed base 0 e. g., ,West Texas and other Mid-Continent crudes. Although the viscosity index of the lubricating oil does not appear to be a critical factor as far as the present invention is concerned, the viscosity index should be between the approximate limits of 0 and 150, and

usually between the limits or about 30 and 100. The particular stocks used may be separated from the crude petroleum by any or the methods commonly used including distillation, extraction with various solvents, e. g., phenol liquefied sulfur I dioxide, eta, having aselective solvent action for aromatic and unsaturated hydrocar ons, etc.,

\ 45 and the fractions obtained mayx-be subjected to 1 will be more fully discussed and incorporated in the lubricant maybe required to v ing capacity. Usually '12 to 15 of lead naph- Y a hydroxy aromatic 1 weight members-of the class too soluble in water for.

any desired refining or purification steps such as of soap and otheradditlon agents used and should normally range between the approximate limits acid-treating, soda washing, clay treating, etc. Theproportion of the mineral oil in the finished lubricant will, of course, depend upon the amount of '70 and 98%, and usually between the limits;- of 80 and 95%. Suitable lubricating oil base.

stock fractions may have Saybolt viscosities ranglag between the approximate limits of 35 to 200 seconds at 210 F., or about 100 to 10,000 seconds at 100' I". s

The soap to be used should-be one derived from a heavy metalsuch as lead, tin, barium,

antimony, etc. Heavy: metals selected from I groups II, IV, and V of the Mendelefl' Periodic Table arepreferred, and of all the metals included within the above scope lead is preferred as th'e most suitable. The acids to be used "in preparing these heavy metal soaps should be- 'naphthenic acids, preferably derived from petroamyl,etc., derivatives of hydroxy leum stocks and they should preferably be obtained from fractions having a boiling range at least as high as that of kerosene or lubricating oil cuts, although naphthenic acids obtained from lighter cuts, such as the naphtha fraction- The desired naphthenicacids are those containing at least one cyclic nucleus and preferably contain more than 8 carbon atoms. They are usually mono-carboxylic in -some cases one may use.

acids'corresponding. to the general formula v where n is an integer between the approximate limits of about 8 and 23 and ranges between 2n and 212-4.

The soaps of the lead naphthenate, are quite different from the present invention, such as:

corre'sponding'heavy metal soaps of high rholecuj lar weight, substantiallystraightschained allphatic carboxylic acids, such as lead oleate, as

The amount of heavy metal naphthenate to be invention will vary according to the desired loadcarrying capacity and the conditions under which the lubricant is tobe used, but will ordinarily range betweenthe approximate limits of band illustrated lateraccording to this 25% by weight of the finished lubricant and usually between the limits of about 5% to 20%.

However, it should also be pointed out that if it is desired to have so-called extreme pressure lubricating characteristics in the lubricant, the amount of heavy metal naphthenate should be subs'tantiallyover 10%, e. g., 12% or preferably 15%, although in some cases even 18 or 20% impart sufllcient load-carry amounts of other addition agents known to the thenate in a mineral lubricating base stock-will,

enable the compounded lubricant'to carrya 43- pound load on the chine. The 'hydroxy added according to the present invention forimlubricant testing ma-l aromatic compound which is proving the water-resistant or water-repellent;v

properties of the lubricant, should preferably be hydrocarbon and should preferably be a hydroxy aromatic compound having a water-solubility less than about 5 grams per 100cc. of water, at 20 distinguishes phen'al (which they simplest member of the hydroiw aromatic class) from cresols and other higher molecular having a more com- Phenol is or the best operationof' this invention although under some circumstances,

plicated, chemical structure.

c. This limitation maybe considered a be used as for instance with some particular type .01 mineral oil base stock and with some particular type of heavy metal soap of some particular fraction of naphthenic acids,- or perhaps where the conditions of use tend to prevent solubility in water,

as for instance under low temperature operating conditions, phenol itself may be utilized. Or-

dinarily, however, one or more of the cresols (ortho-, metaand para-) are preferred. Thepara-cresol is the. best from the point oi view of lowest solubility inwater, but from apractical point of view a commercialmixture called tri-' cresol," which contains derivatives of benzene having one methyl group and one hydroxyl group by having benzene nucleus, is preferred because it is available on the market at relatively low cost. If desired, other hydroxy aromatic compounds may be used such as alpha-naphthol or beta-naphthol or other alkyl, e. g., methyl, ethyl, propyl, butyl,

aromatic compounds containing one, two, or more cyclic nuclei which may be, either condensed nuclei as in naphthalene or linked through a single bond as in the case of diphenyl. Such compounds may also contain two or more hydroxy substituents provided that the water-solubility and oil-insolubility are not so high as to prevent the desired water-repellent characteristics desired for the present invention. These compounds ma if desired, also contain other known hydrocarbon 'substituents, for example, amino groups as in the case of paraamino phenol, benzyl para-amino phenol.

hydroxy aromaticcompound to or imparting the desired water-repellent properties according to this invention will depend The amount of upon a number of factors, such as-the kind and amount of heavy metal naphthenate used and the particulartype of chemical structure of the hydroxy aromatic compound itself,,as well as upon the type of mineral'lubricating oil base stockand the operating conditions under which the lubricant is to be used. Ordinarily, however, the,

amount required would imate limits of 0.1% and narrowed limits of 0.5% and 3%.

Although the three ents, namely, naphthenate be between the approxmineral lubricating oil, heavy metal soap and hydroxy aromatic compound are the three primary constituent lubricants prepared according to this invention, minor art may also be incorporated. For instance, thickthem in diflerent positions around the 5% and usually between above-mentioned ingredieners may be used, especially such as high molec- I ular weight solid polyisobutylene, which has the additional advantage ofimproving the adhesiveness of the lubricant, or in other Words, of iinparting additional stringine'ss; Other dyes may be used, and also small amounts of oxidation inhibitors may be added, although the hydroxyaromatic compounds used according to the present invention for. the Purpose of obtaining desired water-repellent properties, may alsov have oxida tioninhibiting characteristics.

The products of this invention are useful for n For inmany different industrial applications.

stance, in additionto lubrication of the hot strip mill approach tables mentioned previously. e i Z may .also be used for lubricating the bearings in a cold roll mill for fabricating steel products, as

well as for other uses'such' as submerged gear and That the present invention obtainsunexpectedly useful results is indicated'by thefact that it gs in marine vessels, paper mill machinery,

' limiting the assumes has been known for many years that lead oleate willsubstantially improve the load-carrying capacity of mineral lubricating oils for use in lubriby the lubricant during the churning had dropped cating gears and bearings operating under heavy load pressure (but it has been known that lead oleate lubricants will absorb moisture and form an emulsion with water to a substantial degree and that this characteristic, although desirable in some instances, is a disadvantage in most cases). The prior art has, therefore, generally recommended that. when using a lead oleate lubricant cut as a separate layer, thus showing that the lubricant had very substantial water-repellent characteristics. Accordingly a larger sample of this product was used for lubrication of the roller bearings arid gears on one of the approach table.

lubricating oil containing 1 to 10% of a heavy metal fatty acid soap, such as lead oleate, as a solubilizing or stabilizing agent to prevent such soaps from settling out after long standing. For

that purpose the phenol is much more effective than higher molecular weight phenolic compounds, such as'cresol, xylenol, or alpha-naphthol, because to stabilize 4% of lead oleate in a certain lubricating oil stock having a viscosity index of 85, only 1.5% of phenol was required whereas 2% of cresol and 3% of either xylenol or alpha-naphthol were required.

Now the heavy metal naphthenates of the present invention are unexpectedly superior, to the oleates referred to above, because they are soluble in practically all mineral lubricating oils, regardless of the viscosity index, whether high or low, and needs no addition agent either to solubiiize or stabilize blends thereof, as required in the case of 1 lead oleate, particularly with ,high viscosity index oils. It should also be noted that when increasin amounts of lead oleate are used, the amount of solubilizing or stabilizing agent must likewise be substantially increased, but on the other hand.

when the lead naphthenate of this invention is used, increasing the amount thereof apparently does not require any hydroxy aromatic compound to stabilize solution in the oil but also actually drives on a hot strip mill in a large steel plant and it was found to shed water effectively, which was automatically drained of! by difierentlal gravity, water legs, or valves. Further experiments on a laboratory scale showed that 1% of cresol in the above composition was effective as a waterrepellent agent.

, Exmrns 2 7 Another gear lubricant was prepared using the following compositions or materials: a

Per cent Lead naphthenate; 15 Cresol a 2 Heavy mineral oil A Light mineral oil (I l3 Viscosity about 40 seconds-Saybolt at 210 F., viscosity index about 28. I

This compounded lubricant had a viscosity ofabout 110-120 seconds Saybolt at 210 F., and

works better than smaller amounts thereof for the purposes of the present invention, namely, as a water-repellent lubricant, in the presence of a given, small amount of hydrcxy aromatic com- The objects and advantages of the invention will pose of illustration and without the intention of invention specifically thereto.

Exmrnn 1 A gear lubricant was prepared using the fol lowing proportions and materials by weight:

x m t new t 1&0 seconds Saybolt at 210- n, t X a. V vmtsi t amt so second Saybolt at 210' m, viscosity index about 70.

. The lead naphthenate used was Pr pared from naphthenic acids derived from a light lubricating oil fraction of California crude petroleum. A small sample of the above composition was f churned with water in a laboratory mixing ap paratus and after settling for about 24 hours, it

was fund that no ly all of the waterpicke'd up was found to shed water very satisfactorily when used as a gear lubricant on a. hot strip mill, the

same as in Example 1, and had the additional advantage of extreme pressure lubricating characteristics.

Exams: 3

In order tov demonstrate the unexpected superiority of lead naphthenate, as compared to lead oleate, the following test results are set forth.

A series of four lubricants were prepared by using a mineral oil base stock having a viscosity index of'about 40 and a viscosity of about '70 seconds Saybolt at 210 F. Test No. 1 contained 10% lead oleate as the soap ingredient but no cresol. Test No. 2 contained the same amount of lead oleate but contained 2% of cresol; this composition, therefore, corresponds to that recommended in the patent previously referred to, namely, Patent No. 2,031,986 (although the patent states that of phenol is better for solubilizing and'stabilizing purposes than 2 of cresol,and, in fact, with an oil of the viscosity index used here no addition agent is necessary for solubilizing or stabilizing the lead oleate. Test No. 3 contained be better understood from a consideration of the following examples, which are given for the puremulsion.

5% lead naphthenate and 2% of cresol, and Test No. 4 contained 12 "of lead naphthenate with 2% of cresol. The procedure followed in these tests was to weigh grams of each lubricant in a one-liter breaker and add 150 cc. of Monongahela River water three times at intervals of five minutes, the mixture being churned in a Mix-' master at approximately 900 R. P. M.

Through out the tests observations were made as to the thickening. of the mixture, any change of color, and also whether the added water was absorbed bythe lubricant (by which is meant. becoming emulsified, or, at any rate, so finely divided and dispersed within the lubricant that it had the appearance ofa true emulsion) After the third addition of water had been churned into the lubricant, the sample was permitted to stand for a substantial length of time to determine the amount .and rate of water separation from the The results of the above tests are arated is shown graphicallyon a chart in the accompanying drawing. 1

tabulated in the following table and the amount of water sepan 150 cc. has but was not all absorbed Bftel' min. additional churning.

These four testsshow that both 'or the samples containing lead oleate not only'absorbed all of the water in all three additions, but also the re sultant emulsions which were so stable that. little or no water was separated therefrom during the period of observation. A comparison of tests Nos.

1 and 2 indicates that the 2% of cresol was not eflective in preventing the water absorption and had only very slight effect in accelerating the separation of waterfrom the resultant emulsion. On

the other hand, in bothtests Nos. 3 and 4 where 'lead naphthenate was used instead of lead oleate onlythe first addition'ot water was completely absorbed, the third addition was not at all absorbed in either case, and: the second addition of water was only partly taken up intest No. 4 containing 12%% of lead naphthenate but not at water at 20 C.

all taken up in test No. 3 containing 5% of .lead

naphthenate. Likewise, tests Nos. '3 and 4 both metal naphthenate thenate or a metal It is not intended 2,388,088 v Table r Percent Standing 2 mp lstlliOcc. marrow. arduous, um i I E I Tes 8 Water-sep- No. :1 2 Water I Water Water Thiek- Color Thick- Color Thick- Color 3 5 g ening change 2;? ening change an? ening change a s I i 6 2. 6 s

a an--- a Brow'nal't- AIL... Hoar Noiur- AIL...v Q 0 None. i as. a; H... t g min. sion. change. 1 2.. 10 2 None... do.... ..do slilgzht B 65131 -.do Heavy do do 44 Onlyoiight.

a era e i 3min. min. 35min 3 5 2 Began Brown.- do 4 N o t 110.4-.. Nat 3 4d flayyzrsz tgp 1 g ickken =ken hot. 40%

en. up.. up. water. 4.-..- 12K 2 None". Dgrk do stringy. Lighter... P ayrtd do 1 l5 zl yimfip rown m ken water.

In the appended claims the expression fheavy is intended to mean a naphof mineral lubricating oil, about 5-25% by weight of a lead soap or naphthenic acids containing at ast one cyclic nucleus, and a small amount of a hydroxy aromatic hydrocarbon havinga watersolubility less than about 5 grams per 100 cc. of

- 2. Lubricant according to claim .1 containing about 0.1 to 5% of creso.

showed a fairly rapid separation of water when the mixture was allowed tostand, since in test No. 3 after 2%hours of standing two layers were formed, consisting of a' bottom water layer representing 40% of the total volume and an'upper lubricant layer representing 60% of the total vol.-,

ume; whereas,.test No. 4-showed a still more rapid separation, namely, a 50% water and 50% lubri-- cant separation after only 1 hours. The chart showing these water separation test results demonstrate graphically the very great superiority of the lead naphthenate in tests Nos. 3 and 4 as compared to the lead oleate. in tests Nos. 1 and 2. In all of the examples discussed above, the lead naphthenate used was prepared from naphthenic acids obtained fro a California (naphthenic base) petroleum fraction falling within thegas oil boiling range. The cresol used in all ofv the above examples product called"tri-cresol which consists of a 1 mixture of the ortho-, meta-, and paraforms of cresol. In each 'case the lead soaps'were first added to the mineral oil and the cresol added last.

I major proportion 45.

was a semi-refined commercial 3 in contact with water containing fairly largeamounts to. promote emulsificatiam'itis conceivable, of course, that there may be limits to the amount '01 such emul'siflcation-promoting impurities which can becounteracted or overcome by the.

use ofthe water-repellent extreme pressure lubricents of this invention. v I

of acids, mineral salts, etc. which tend per cc. of water at 20 C.

3. An extreme pressure lubricant comprising a of mineral lubricating oil, more than 10% by weight of a lead naphthenate and a small amount oi a'hydroxy aromatic compound having a water solubility less than about -5 grams 4. An extreme pressure lubricant comprising a major proportion of mineral lubricating oil, more than 10% taining at least one cyclic nucleus and derived v high as kerosene, and about 0.5 to 3% by weight -5. The method 01' lubricating moving metal parts where the lubricant must at least 'come in contact witlrwater, which comprises using as the lubrlcanta composition comprising a major proportion" of mineral lubricating oil, at least 5% of 5. lead naphthenate and a small amount of hydroxy aromatic compound havinga water solubility less than about 5 grams per 100 cc. of water a 20 C. a r 8. The method of lubricating. moving metal parts which contact each other under extreme pressure and where the lubricant must at "least occasionally come in contact than 10% by weight W h 0 g MAURICE nnswrcx.

at least about as heavy as tin.

that the invention be limited to any of the specific examples given nor unoilead soap oi naphthenic acids conof cresol, the amount of the latter. being sufllcient to make the entire compounded lubricant substantially water-repellent.

with water, which, comprises lubricating said metal parts :with a. composition comprising a major proportion 01" mineral lubricating oil, more of lead naphthenate and ,about 0.5 to 3% by 

